Seoul closely monitoring N Korea for 'missile launch': Military

South Korea's military said it was closely monitoring North Korean facilities after a series of satellite images triggered international alarm that Pyongyang might be preparing a long-range missile or space launch.

Analysis indicates increased activity at two key sites -- the Samundong missile research facility and the Sohae rocket-testing facility.

Any launch could send stuttering talks on denuclearisation into disarray.

South Korea is "closely tracking and looking into all activity for possible scenarios including a missile launch" across the border, in close coordination with the U.S, said Kim Joon-rak, spokesman of the Joint Chiefs of Staff.

Satellite images of Samundong taken on February 22 showed cars and trucks at the site, as well as rail cars and cranes at a yard, U.S news outlet 'NPR' reported.